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Old Jan 26th 2018, 07:40 PM   #41
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Originally Posted by yafimski View Post
Hi,
Sorry to ask these simple questions again but I'm not sure what to do.

I have the 'coil 1' I mentioned in the above posts. It's a tiny solenoid with DC12V on it.

I tried to attach the coil to the +/- of the battery and just bring it close to the magnet but it didn't differ from my previous trial - meaning the magnet just doesn't seem to be affected by the coil's magnetic field.

The battery I used is still the 9v.
Should I split an old laptop charge's cable and connect it to the wall?

Thanks
Ahh ... only just seen this post .... the problem is this 9V battery ,it will do nothing ....

If you have an unwanted laptop power supply this can be useful .... this consists of a black box perhaps 15 x 5 x 3 cm ... one wire goes to the mains socket (power in) .... another wire coming out, plugs into the laptop and is DC voltage out , perhaps 19 V .... with the power supply disconnected from the mains cut off the plug that normally goes into the laptop . This will allow you to access the two wires that deliver the output voltage , connecting them to your coil should get some results , check the output voltage first, if bigger than the coil recommended voltage you may want to put some resistance in series , check the current with your meter in series (10A setting).

Last edited by oz93666; Jan 26th 2018 at 08:44 PM.
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Old Jan 30th 2018, 05:12 AM   #42
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Safely does it.

The problem is not with the voltage, it is with the amperage.
Most 9V batteries are designed for powering small transistor circuits, which require a low amperage.

If you join batteries in series you will get higher voltage, but the same amps
If you Join Batteries in parallel, you can draw more amps, at the same voltage.

If you can get several 9V batteries, and join them in parallel, you might start to get enough "umph" out to properly drive your solenoid.

Alternatively start with batteries that are designed to deliver a higher amperage (at lower volts) like bicycle lamp batteries.

Remember linking 2 in series doubles the voltage,
linking 2 in parallel doubles the amperage (to a reasonable approximation).
so by linking 4 in a combination of serial and parallel you could double both the volts and amps.

by linking 8, or 16 or, etc...

Be careful if you start linking lots of batteries together,
it is safer than mucking around with mains driven transformers, but you can still get a nasty belt of a stack of batteries.
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Old Jan 30th 2018, 09:08 AM   #43
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@Woody

Do you think that parallel 9v should be better than a laptop charger...?

What is your recommendation?

Thanks
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Old Jan 31st 2018, 02:02 AM   #44
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You want a lot of power in a short time,
A laptop charger is designed to give a trickle of power over a long time.

If one were to open a 9V battery
(not recommended, there are some moderately nasty chemicals inside)
you would find 6 little 1.5V batteries, arranged in series.
(The chemistry of batteries means that a single cell will give 1.5V,
these then need to be stacked to get higher voltages)

Note that the individual 1.5V cells in a 9V battery are quite small,
and so are individually only able to supply a small amount of power.

I would try taking lots of the larger style of 1.5V batteries
(the old fashioned type used for hot filament bulb bicycle lamps,
before high efficiency white LEDs were developed)
and arrange them in a grid, perhaps 5 or 6 long, by 3 or 4 wide.

6 stacked in series will give 9V,
3 of these stacks, linked in parallel will give 3 times the power of 1 stack.
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Old Mar 26th 2018, 01:25 PM   #45
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Hi Woody,

I've tried connecting five 9v batteries together. It doesn't seem to have a repulsive effect on the neomagnet.

Can you tell me what is the way to connect the batteries-solenoid-neomagnet experiment in a way that the motor should repel the magnet..?

Thanks
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Old Mar 27th 2018, 05:01 AM   #46
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Connect all the positive battery terminals together
Connect all the negative battery terminals together

This will give you an output of 9 Volts (the same as each individual battery)
but it will be able to deliver 5 times more power than the individual 9V batteries.

I don't know if this will be enough, or not.
9V batteries are actually quite feeble,
they are designed to have a gentle touch for use with delicate transistor circuits,
not for brute strength physical processes.
Brute strength batteries will be physically larger, but with a smaller voltage
(typically 1.5V)

Have you tried the magnetic strength of your solenoid on its own?
(rather than in direct competition with the neomagnet)
How many (small) steel nails will the solenoid magnet pick up?
How many of the same type of nail will the neomagnet pick up?
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Old Mar 27th 2018, 05:59 AM   #47
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Stop wasting your time with these (domestic) 9v batteries ...

You will get nowhere with them

You need a car battery , even one which is no longer powerful enough to start a car and has been scrapped ....

or start recycling scrap laptop batteries ... it's a big thing at the moment , I've just bought 30Kg to build my own storage system check out Youtube ... people make powerwalls from the cells for off grid solar electricity ...
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Old Mar 28th 2018, 02:22 PM   #48
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comparing solenoid and neodyme strength

Originally Posted by Woody View Post
Connect all the positive battery terminals together
Connect all the negative battery terminals together

This will give you an output of 9 Volts (the same as each individual battery)
but it will be able to deliver 5 times more power than the individual 9V batteries.

I don't know if this will be enough, or not.
9V batteries are actually quite feeble,
they are designed to have a gentle touch for use with delicate transistor circuits,
not for brute strength physical processes.
Brute strength batteries will be physically larger, but with a smaller voltage
(typically 1.5V)

Have you tried the magnetic strength of your solenoid on its own?
(rather than in direct competition with the neomagnet)
How many (small) steel nails will the solenoid magnet pick up?
How many of the same type of nail will the neomagnet pick up?


Hi,
With regards to seeing which is stronger, I've tried it and it seems that the neomagnet is WAY stronger, at least x10 if not x20...

What would you recommend I do in terms of components and connections to actually repel a neomagnet? That is my end goal, to repel it a few centimeters...

Thanks!
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Old Mar 28th 2018, 03:55 PM   #49
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I've just had a quick look at an online site for buying batteries
and one of the terms they use for describing the applications that particular batteries are suitable for is "high drain" or "low drain"

Your solenoid will definitely fall into the high drain category, but 9 volt batteries are designed for low drain applications.
If you use a low drain battery in a high drain application, it will simply fail to deliver the advertised voltage.

I would use a stack of C or D type 1.5V batteries.
These can be stacked end to end to increase the voltage,
(2 for 3 Volts, 4 for 6 volts, etc...).

They can also be placed side by side to give extra strength (maintain the voltage under a higher drain)

The attached image shows an example with two end to end battery stacks linked side by side.
If each battery is a 1.5V then this pack will supply 3 Volts
Attached Thumbnails
Neodymium magnet and electromagnet experiment-batteries.jpg  
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Old Mar 28th 2018, 07:21 PM   #50
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Originally Posted by Woody View Post
I've just had a quick look at an online site for buying batteries
and one of the terms they use for describing the applications that particular batteries are suitable for is "high drain" or "low drain"

Your solenoid will definitely fall into the high drain category, but 9 volt batteries are designed for low drain applications.
If you use a low drain battery in a high drain application, it will simply fail to deliver the advertised voltage.

I would use a stack of C or D type 1.5V batteries.
These can be stacked end to end to increase the voltage,
(2 for 3 Volts, 4 for 6 volts, etc...).

They can also be placed side by side to give extra strength (maintain the voltage under a higher drain)

The attached image shows an example with two end to end battery stacks linked side by side.
If each battery is a 1.5V then this pack will supply 3 Volts
I can tell you from decades of hands on experience with this type of stuff this will also get nowhere .. no domestic 1.5V will do anything ...unless you buy literally about 100 of them , and wire them in series and parrell

But don't believe me , go and buy some and tell us what results you get .
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